Some operations are VERY slow

I've just started using Goyo, thanks so much for making it!

I've noticed immediately that some operations are extremely slow. So far any pasted in content from another application, regardless of length, basically hangs for a while.

Reproduce the reported slowdown by pasting content from another application while Goyo is active, then identify which operation causes the hang. No file, test, or entry point is named; done would mean pasted content is handled without the reported delay.

Written by the indexing model from the issue text.